Machine tool transmission and control mechanism



Sept. 1.7, 1946. 1 J. B. ARMITAGE ET AL 2,407,913 MACHINE TOOLTRANSMISSION AND CONTROL MECHANISM Filed Feb. 23, 1942 9 Sheets-Sheet lw a. E 39 m W I m 5X ATTORNEY.

Sept. 17,1946. 2,407,913 MACHINE TOOL TRANSMISSION AND CC JNTROLMECHANISM J. B. ARMiTAGE ET AL 9 Sheets-Sheet' 2 Filed Feb. 23 1942NTORS a. a 7 M E Mi n w m 5. wmu aw Sept. 17,.1946. J. B. ARMITAGE E TALMACHINE TOOL TRANSMISSION AND CONTROL MECHANISM Filed Feb. 23, 1942 9Sheets-Shee't 3 ATTORNEY.

I Sept. 17,1946. J. B. ARMITAGE ET AL MACHINE TOOL TRANSMISSION ANDCONTROL MECHANISM 9 SheetS-Sh eetA' Filed Feb. 23, 1942 INVENTORS:

Sept. 17, 1946.

J. B. ARMITAGE ET AL MACHINE TOOL TRANSMISSION AND CONTROL HECHANII ISH9 Sheets-sheaf 5 INVENTORS: Y Jwwwa-naM/Mm'a BY: om?! W-MRKER- 7 (V Cw nATTORNEY.

Filed Feb. 23, 1942 p .6- J: B. ARMlTAGE -ET AL 2,407, MACHINETbOLTRANSMISSION AND CONTROL MECHANISM Fileq Fe 23, 1942 9 sheets-sheet eSept. 17,1946. J. B. ARMITAGE ETAL 'HACHINE TOOI; TRANSMISSION AND-CONTROL MECHANISM Filed Feb. 25, 1942 9 Sheets-Shet 7 Ill vlllll/lllllll/ll/l/l/lll/lllllllllll/Ml/l/ll,

| /IIII/l/Il/II/IIIllIIIIIMIIIIIIIIIIIIII///IIII/II l//Ifl/l/l/I/I/IW/Ill/II/l/I/lIIIIIIIII/{IIIIIIW JwL-X W WMHZW ATTORNEY.

Sept. 17, 1946.

J. B. ARMITAGE ETAL.

MACHINE TOOL TRANSMISSION AND CONTROL MECHANISM Filed Feb. 2:; 1942 9Sheets-She et8 & V

ORNEY.

Sept. 17, 1946.- J. B. ARMITAGE ET AL 2,

MACHINE TOOL-TRANSMISSION AND CONTROL MECHANISM I Filed Feb. 23, 1942 9ShetS-ShBGt 9 A III/III ill/111W nTTuRNEY;

Patented Sept. 17, 1946 MACHINE TOOL TRANSMISSION AND CONTROL MECHANISMJoseph B. Armitage, Wauwatosa, and .Orrin W. Barker, Milwaukee, Wis,assignors to Kearney & Trecker Corporation, West Allis, Wis., acorporation of Wisconsin Application February 23, 1942, Serial No.431,908

20 Claims.

This invention relates, generally, to machine tools and moreparticularly to improved machine tool operating and controllingmechanism of the type especially adapted for utilization in millingmachines.

A general object of the invention is to provide improvedstructuralarrangements and actuating mechanism for a machine .tool

Another object is to provide an improved power transmitting mechanismfor actuating the movable elements of a machine tool;

Another object is to-provide animpro-ved transmission mechanism andcontrolling apparatus arranged to be removable from a machine tool as aunit to facilitate inspection and maintenance thereof;

Another object is to provide an improved control mechanism for theoperating elements of a machine tool;

Another object is to provide an improved hydraulically actuated controlapparatus for a milling machine;

Another object is to provide an improved auto, matic reversing tripmechanism for a movable element of a machine tool;

Another object is to provide an improved clutch actuating controlmechanism for a machine tool.

A further object is to provide an improved driving arrangement for aWork supporting table of a machinetool.

According to this invention, a milling machine is provided with animproved spindle driving mechanism arranged to afford a @ries of spindlespeeds in two ranges. Likewise, an improved rate changing feedingmechanism for the Work supporting tabie is provided with pick-oil changegears and an improved hydraulic automatic reversing mechanism, thehydraulic mechanism being mounted with the pick-oil gearing toconstitute a unitary structure that is readily removable from themachine for inspection. The hydraulic control system includes improvedmeans for effecting automatic reversal into movement at either feed orrapid traverse rate, and actuates-an improved selective main clutchcontrolling systemthat may be utilized for stopping the spindleautomatically when the rapid traverse drive is engaged.

The invention is exemplified herein by an embodying machine toolstructure, but it is to be understood that the particular apparatus setforth is intended to be illustrative only and that the variousindividual characteristics may be embodied in other structural forms,all coming within the range ofequivalents of the features defined in thesubjoined claims.

The foregoing and other objects of this invention, which will ,be morereadily discerned from the following detailed description, may beachieved by means of the illustrative apparatus depicted in, anddescribed herein in connection with, the. accompanying drawings inwhich:

Figure 1 is a general View in front elevation of a milling machineexemplifying the type of machine tool in which the present invention maybe incorporated to advantage;

Fig. 2 is a view in side elevation of the milling machine shown in Fig.1, with parts broken away;

Fig. 3 is a detailed view in perspective of a clamping device for theoverarm structure of the milling machine;

Fig. 4 is a partial view in perspective, showing the vertically movablespindle carrying head;

Fig. 5 is a View partly in plan and partly in horizontal section takenalong the line 5-5 in Fig. 1.

Fig. 6 is anenlarged view in rear elevation of the milling machine withparts broken away to show internal mechanism;

Fig. .7 is an enlarged view largely in vertical axial section throughthe spindle carrying block, showing the spindle driving transmissionmechanism;

Fig. 8 is a detailed View of the gear shifting mechanism in the spindletransmission;

Fig. 9 is a view in perspective of the gear shifting yoke;

Fig. 10 is a fragmentary sectional view of one end of the worksupporting table showing the screw supporting bearing bracket, takenlargely in vertical section along the line l0.lil in Fig. 2;

Fig. 11 is a fragmentary plan view of an improved table screw drivingmechanism;

Fig. 12 is an expanded diagrammatic viewof the spindledriving speedchanging train;

Fig, 13 isa fragmentary View in vertical section through the bed ofthevmachine, taken along the line .!3l 3 in Fig. 1, showing the tabledriving power transmission train;

Fig. 14 is afragmentary view taken in horizontal section along the lineMI4 in Fig. 13;

Fig. 15 is an enlarged fragmentary View in vertical section taken alongthe line 15-15 of Fig. 1, showing the trip mechanism for controlling themovement of the work supporting table;

Fig. 16 is an enlarged View of the tripping post 3 hydraulic controlsystem for effecting automatic operation of the milling machine.

The particular machine tool illustrated in the drawings as exemplifyinga practical embodiment of the principles of the present invention, is amilling machine of the bed type, similar in general form and arrangementof parts to the milling machineshown in United States Patent No.2,118,357 issued May 24, 1938.

Referring more specifically to Fig. l of the drawings, the millingmachine there shown comprises essentially a hollow bed or base 29 thatconstitutes the main supporting frame of the machine and forms a housingfor the driving and controiling mechanism.

On the upper forward surface of the bed 29, a work supporting table 2iis slidably mounted for reciprocating movement longitudinally of thebed. At the rear of the table, a pair of uprights 22 and 23 are securelyfixed to the upper surface of the bed 2! in spaced relationship and arejoined at the top by a cap 24') to constitute a rigid upstanding columnstructure. As shown, in Fig.2, the column structure serves to support a,rotatably mounted tool spindle 2E5 in cooperating relationship with thework table 2 I.

To provide for adjusting the position of the spindle 2% relative to thwork table 2 l, the spindle is carried by a spindle supporting head orblock 2'! which is slidably mounted between the uprights 22 and 23 forvertical movement. Ad-

fjustment of the vertical position of the spindle head is effected byturning a combined hand bolts 38 which operate in T-slots 39 in theforward faces of the uprights and project through the lugs 34 and 35 ofthe head to clamp them for axial movement in. the head 21, as shown inFigs. 2 and 7. Axial adjustment of the position wheel and nut 28 whichabuts against the top of the cap 24 and has threaded engagement with ascrew 29 the lower end of which is fixed in the spindle block 2'5, agraduated dial 38 being pro- ,disposed vertical guiding ways 32 and 33,respectively. The forward sloping surfaces of the angular ways havesliding engagement with complementary angularly disposed surfaces formedin the uprights 22 and 23. At its forward edge, thespindle block 21 isprovided with laterally projecting lugs 34 and 35 which have slidingengagement with flat ways formed in a common plane on the forward facesof the uprights 22 and 23 respectively. The angular way 33 on the headis provided with an adjusting gib 31 which may be tightened to effectaccurate sliding engagement between the head and the uprights. As mayreadily be seen, when the gib 31 is tightened it moves into engagementwith the complementary way in the upright 23 and draws the lug 35against the forward face of the upright.

Simultaneously, the wedging action of the gib upon the angularlydisposed sliding surface of the upright 23 forces the entire head 2! tothe left and effects a similar wedging action between the slopingforward face of the way 32 and the plane face of the lug 34 upon thecomplementary surfaces of the upright 22, clearance spaces beingprovided between the other surfaces-of the head and the uprights asindicated in the drawings. This arrangement provides for effecting closeadjustment between the sliding head and the cooperating ways of thecolumn structure to insure accurate movement of the head. After the.spindle head has been adjusted to bring the spindle 25 to the desiredvertical position, by

turning the hand wheel 28, the head 21 may be.

locked to the uprights by tightening clamping of th quill is effected byturning a hand wheel 44 at the side of the upright 23, the hand wheelbeing operatively connected to the quill in well known manner andprovided with a graduated dial 45 to indicate the longitudinal positionof the spindle. After the spindle quill has been moved to an adjustedposition, it may be clamped to the spindle block by turning a clampingnut 46 which draws a clampingelement t! into engagement with the quill,as shown in Fig. '7.

Above the spindle 26, a pair of overarms 5| and 52 are slidably mountedin the spindle block 21 in manner to extend forward to support a cuttercarrying arbor, as shown in Fig. 2, the arms being connected at theirforward ends to the bed 20 by means of a harness structure 53. As bestshown in Fig. 6, the upper part of the head 21 is provided with a kerf54 extending horizontally between thearm receiving bores to provide aresilient portion that may be deflected for clamping the arms. For thispurpose, a clamping screw 55 is provided between the arms at each end ofthe head 21, the screws being fixed in the head beneath the kerf 54 bymeans of pins 55, threaded on the upper ends of the screws 55 in mannerto bear-upon the top of the head and are adapted when tightened todeflect the upper portion of the head 21 into clamping engagementwiththe overarms. To provide for tightening the two clamping nutssimultaneously, each nut is fitted'with an arm 53 the arms beinginterconnected by a link 59 pivoted at its respective ends to the end ofeach arm. As shown, the forward sure exerted at the respective ends ofthe head 21. This arrangement provides for correcting any inequalitywhich may result from wear between the nuts and the screws or the head,since the arms may be removed readily from the nuts at any time andre-engag'ed with th nut serra tions at the position of adjustmentproviding for equal clamping pressures. l

Power for moving the Work table 2| and for. rotating the cutter spindle26 is derived from an electric motor 6! mounted in the hollow bed 20, asindicated in Fig. 6, and connected by multiple belts 62 to a maindriving pulley 63. As best shown in Fig. 13, the driving pulley 63 isrotatably mounted at the rear of the bed by means of an inwardlyextending hub 64 journalled in a pulley bracket 65 secured in an openingat the back of the bed, the pulley and belts being enclosed within ahousing 66 provided with a hinged covenportion 61. 1 For transmittingpower to Clamping nuts 51 are 7 feed rate, the pulley (i3 is selectivelyconnected, by means of a clutch it], to a main driving shaft 'II thatextends through the bed to the front of the machine.

Power for rotating the spindle 26 is taken from the main shaft 7 I bymeans of a worm 12, shown in Figs. 13 and '14, that is fixed on theshaft and has meshing engagement with a worm wheel 13 rotatablysupported in the bed 26. The worm wheel 73 has splined connection with averticall'y disposed splined shaft T4 that is journalled in the spindlehead 2? and arranged for vertical movement therewith, the splinedconnection with the worm wheel '13 providing a driving connectionregardless of the vertical position of the spindle head. The verticalshaft i i delivers power at constant speed to a bevel gear reversingmechanism 75 in the spindle head 2?, as shown in Fig. For effectingreversal in the direction of spindle rotation, the reverser may be actuated by a shifting arm T6 to provide for coupling the vertical shaft "[4to a horizontal power driven shaft '1'! in manner to drive it in eitherdirection for turning the spindle in either direction selectively.

From the horizontal power driven shaft 7"! in the head 21, power istransmitted to drive the spindle at a selected rate in either of twospeed ranges. 'Whenoperating in the high speed range, power from theshaft 11 i transmitted by a pickoff gear 19 removably fitted on the endof the shaft, to a complementary pick-01f gear 80 similarly fitted onthe end of a parallel spindle driving shaft 8! The shaft 8! is providedwithin the spindle head 27 with'a long pinion $2 that meshes with alarge gear wheel 83 fixed on the spindle 26 in the rear of the quill 43,the arrangement being such that the gear wheel 83 may slide along thepinion when the spindle and quill are adjusted axially withinthe head21.

As may best be seen by reference to Figs. 6 and 7, the pick-off" gears'59 and 80 are mounted on the rear face of the head 27 and are protectedby means of a hinged cover plate or door 34 which may be opened toprovide access to the gear receiving ends of the shafts. Alternativesets of pickoff gears arranged to provide a series of spindle speeds,are stored in covered recesses 85 at the rear of the bed, as shown inFig. 6.

For driving the spindle in the low speed range, there is provided aspeed reducing or range changing intermediate or back gear mechanismarranged to transmit power indirectly from the power driven shaft '11 tothe spindle driving shaft 81. As may best be seen in the diagrammaticView, Fig. 12, the intermediate speed reducing mechanism includes ashiftable pinion 87 that may be moved into meshing engagement with acomplementary gear 83 on the spindle driving shaft 8|, a shifting fork89 being provided for this purpose. The pinion 8'! has associated withit agear wheel 90 which meshes with a long pinion 9| fixed on-anintermediate shaft 92, the arrangement being such that the gear 5!! mayslide along the pinion 9i when the pinion 81 is shifted into or out ofmeshing engagement with the gear '88. The intermediate shaft 92 isprovided at its end 93 withmeans'f'or receiving a pick-off gearadaptedto mesh with a complementary pick-off gearon thedriven shaft Ti.The pair of pickoff gears transmitting power from the driven shaft 11 tothe intermediate shaft 92 replace the pick-01f gear direct drivingconnection between the shaft 11 and the spindle driving shaft Bl rep- 6resented by the gears T9 and shown in .Figs. 6, 7-and 12 in thedrawings.

Since the driving mechanism would be locked, and injury might possiblyresult to the machine if intermeshing pick-off gears should be appliedto both the shaft '81 and the shaft 92 at the same time, means areprovided for preventing the :application of a pick-off gear to the shaft8! when the intermediate pinion 81 is meshed with the gear 88 fordriving the shaft 8|. As shown in Fig. 8 of the drawings, the shiftingfork 89 associated with the pinion 81 is provided with an actuating rod55 that extends through th rear Wall of the head 21 into the pick-offgear compartment and is provided at its end with an actuating handle s'swhich is accessible when the hinged door 8 3 is open, the arrangementbeing such that the handle 96 may be rawn outward to engage theintermediate drive and moved -inwardto disengage the drive. Topreventapplication of a pick-off gear to the shaft 81 when the pinion 8is engaged with the gear'fit, the shifting rod is provided with aninterlocking or interfering member 97 so arranged that it moves outwardinto the space otherwise occupied by the pick-off gear on the shaft 8!when the handle 96 is pulledout to engage the pinion 31' with the gear88, thus preventing a pick-off gear from being placed on the end of theshaft fli while the intermediate speed reducing mechanism is engaged.Furthermore, this interlocking arrangement compels disengagement of theintermediate drive when it is desired to operate in the high speed rangewith a pick-eff gear on the shaft 8i. This is desirable even though nopickoff gear is applied to theshaft 92, since with the spindle drivingshaft 8! operating in the fast range, the intermediate shaft 92 would beturned at excessive speed which would result in undue wear of themechanism. In the event that a pick-off gear should be applied to theshaft 92 when operating in the high speed range, and meshed with eitherthe pick-oif gear H on the shaft ll or the pick-off gear 59 01! theshaft ti, no harm would be don since, with the pinion tl shifted out ofmesh, this would result merely in turning the intermediate mechanismidly at moderate speed.

The work supportingtable 2| is driven to re into semi-cylindricalsockets H95 in the lower surface of the tableends between Ways i titwhich slide oncomplementary surfaces formed in the bed 28, thearrangement being such that the ways extend to the ends of the table andserve to cover and protect the complementary surfaces in the bed at alltimes. As shown in Fig, 1.,the table brackets are secured to the lowerside of the table by means of cap screws [61.

As best shown in Fig. 11, the Stationary nut H32 is mounted in a plateor bracket H0 that is secured by cap screws Hi to the top of the bed 2flbetween the table receiving bearing surfaces. The bracket H0 alsocarries a bevel gear reversing mechanism H2 arranged to drive the tablescrew in either direction selectively. As shown,

the reversing mechanism includes a sleeve H3 having splined connectionwith the screw IOI for rotating it and provided on its peripher withserrations. The serrations on the sleeve II3 are engaged by internalserrations in a complementary shifting collar H4 provided at its endswith clutch teeth that may be shifted into engagement with either of twobevel clutch gears H5 and H6 rotatably mounted in axially spaced bearingelements secured to the bracket I I0. The clutch gears H5 and H6 arearranged to be driven continuously in opposite directions by means of anintermeshing bevel gear III journalled in the bracket III] and havingsplined connection with the splined upper end of a vertically disposedtable driving shaft I20. As may be seen by reference to Figs. 11 and 15,the table driving screw IOI and its associated feed nut and reverse geardriving mechanism on the bracket IIO, may all be removed from the bed ofthe machine as a unit. A protecting cover I2I, shown in Fig. 11, issecured by screws to the upper surface of the bracket Hi] to protect thetable driving mechanism from dustor other foreign matter.

In order to remove the table screw and its driving mechanism with thebracket III), the

table brackets I03 and I 04 are first detached from the ends of thetable by withdrawing the securing cap screws I07. The table may then beremoved from the bed by sliding it endwise along the bearing surfaces,leaving the screw in its original position. After the table has beenremoved, the protecting cover I2I may be detached to expose the capscrews II I. The cap screws III are then withdrawn and the bracket III]lifted to disengage the bevel gear II! from the splined upper end of theshaft I20, whereupon the brack et I I0 together with the table screw,end brackets, feed nut and reverse gearing may be removed fromtthemachine as a unit.

The vertical table driving shaft I is arranged to be driven inpredetermined direction continuously at either a selected feed rate orrapid traverse rate, the driving power being applied to the screw IOI inone or the other direction selectively in accordance with the positionof the shifting collar II L As appears in Figs. 13, 14 and 15, the

' vertical table driving shaft I20 is journalled in a bracket I23 whichalso carries the table feed rate changing and controlling mechanism andis mounted in an opening at the front of the bed 20 for removaltherefrom as a unit.

Power for actuating the table at feed rate is derived from the mainshaft II to which it is transmitted from the motor 5| through thespindle controlling clutch III. As shown in Fig. 13, the shaft II isconnected by means of a splined I coupling I24 .to a shaft I25 that isjournalled in the bracket I23. transmitted through reduction gearingFrom the shaft I25, power is I26 of fixed ratio to a pick-off gearmechanism I21 arranged at the front of the bracket I23 and madeaccessible by opening a hinged door I28. By .fitting gears of the properratio in the pick-off mechanism, the power may be transmitted at anydesired feed rate to a worm shaft I29, spare gears for the pick-offmechanism being retained in a storage compartment closed by anotherhinged door I30 at the front of the machine, as shown in Fig, 1. Thefeed rate worm shaft I29 is provided with a worm I3| which meshes with aworm wheel I32 mounted concentric with the vertical table driving shaftI20, as shownin Fig. 15. A driving connection between the worm wheel I32and the vertical shaft I20 is effected by means.

I31 extending forward to the table feed bracket I23, the arrangementbeing such that the table may be actuated at rapid traverse rateregardless of whether or not the main clutch I0 is engaged to drive thespindle 2B. As shown, the shaft I3! is splined at its forward end to ahollow shaft I38 journalled in the bracket I23 and carrying a spiralgear I39 which meshes with a complementary spiral gear I40 fixed on aclutch housing I II mounted concentrically with the vertically disposedtable driving shaft I20. The rapid traverse driving mechanism may beconnected selectively to actuate the table 2I by engaging ahydraulically actuated friction clutch I42 mounted in the housing I 4|.In changing from rapid traverse rate back to the predetermined feed rateof movement, the rapid traverse clutch I42 is disengaged by releasinghydraulic pressure thereon and a synchronizing friction clutch I43 isforced into engagement by a sprin I44 to quickly reduce the drivingspeed to that of the overrunning clutch I33 in the manner set forth andclaimed in United States Patent No. 2,215,684. a

By thus arranging the feed and rapid traverse rate selecting clutchmechanism on the vertical table driving shaft I20, a direct and positiveconnection is afforded from this mechanism to the table actuating screwIIlI. Furthermore, this arrangement facilitates disconnecting thedriving mechanism for removing the feed bracket I23 from the machine.

As may be seen by reference to Fig. 13, the feed bracket I23 may beremoved from the machine bed as a unit by first detaching the pulleybracket 65 from the bed and withdrawing it a sufficient distance todisengage the splined ends of the shafts II and I3! from the splinedcoupling I24 and the splined hollow shaft I38 respectively. The bracketI23 may then be detached from the front of the machine bed bywithdrawing the cap screws I46 that retain it, whereupon the bracket maybe lowered within the bed to disengage the splined vertical shaft I23from the table driving bevel gear III. This frees the bracket from allmechanical connection with the machine structure and upon disconnectingan oil suction pipe the bracket and its associated apparatus maybe-withdrawnforwar'dly out of the bed 23 to provide access to the entiretable driving and control mechanism for inspection andrepair.

The rate and direction of power movement of the table 2| may becontrolled manually by actuating a lever I50 pivotally mounted on thefront of the machine as shown in Figs. 1, 2 and 15. The direction ofmovement of the table 2I is controlled by swinging the lever I50 to theright or left, as indicated by the arrows in Fig, 1, the arrangementbeing such that the table is thereby caused to move in the correspondingdirection. As shown in Fig. 15, the lever I50 is carried by a pivotallymounted sleeve I5I provided at its inner end with a bevel gear segmentI52 which meshes with a complementary bevel gear segment I53 fixed on aVertically disposed tripping sleeve I54. The sleeve I54 is provided atits other side with a reversed bevel gear segment I 55 which meshes inturn with a complementary segment 555 fixed on the end of a reversingshaft I57. The reversing shaft I51 is provided at its inner end with aspur gear segment I58 which meshes with a rack I59 on a slidably mountedshifting fork I69 which engages a central groove in the reversing collarH4. The arrangement is such that when the lever I59 is in the central Orneutral position shown in Fig. 1, the collar .II' i is in the disengagedposition shown in Fig. 11. Movement of the lever to the left causes thecollar I I4 to move to the left into engagement with the clutch gear H5,which results in driving the table to the left. Conversely, when thelever is moved to the right the collar engages the clutch gear H6 anddrives the table to the right.

Control of the rate at which the table moves is effected by tilting thelever I 50 toward or from the machine. As shown in Fig. 15, the leverI59 is pivotally connected to the sleeve I5I in a manner to permittilting movement and is arranged to engage with its lower end a slidingcontrol rod I6I. The control rod I9I moves in and out in accordance withmovement of the lever I59 and turns a bell crank I62 which engages andeffects vertical movement of a tripping pest I64. The lower end of thetripping post IE4 abuts against a plunger I66 of a rate selector Ifiland engages a rapid traverse valve actuator, the arrangement being suchthat when the lever IE9 is moved forward or away from the machine, thetripping post Iii-I- moves upward, causing the rapid traverse valve toadmit pressure to the rapid traverse clutch mechanism I42 therebyengaging the clutch and causing the table to move at rapid traverserate.

As shown in the enlarged view, Fig. 16, the tripping post I 94 ismounted within the tripping sleeve I. 5 and is provided with a detentmechanism I69 arranged to retain it in either its upper or lowerposition. Automatic change in the rate of movement of the table whilethe machine is in operation, is effected by means of suitable rapidtraverse trip dogs mounted in T slots I "II and I12 in the forward edgeof the table ZI, the arrangement being such that the dogs move thetripping post I54 up. or down as they pass, to change the rate of tablemovement from feed to rapid traverse or vice versa. Other trip ping dogsmay be provided to stop movement of the table at any predeterminedposition, these stop dogs being arranged to contact wings I14 on thetripping sleeve i5 1- and functioning to turn it to its central orneutral position, thereby disengaging the reversing collar I! from itscomplementary clutch gear.

The main driving clutch M for controlling the spindle and the feed ratetable driving mecha nism is arranged to be actuated hydraulically toconnecting position or to disconnecting position in response to movementof a manually actuated clutch controlling lever II'I mounted at theright front of the machine as shown in Figs. 1 and 2. the clutch beingarranged for automatic hydraulic operation also, in order to provide forstopping the spindle automatica ly when the talole is moved at rapidtraverse rate. Referring now to the hydraulic circuit shown in Fig. 17,pressure for actuating the main disconnecting clutch "i9 is derived froma gear pump I19 that is connected to the end of the rapid traverse withan exhaust port I98.

an exhaust port I98.

it turns a control shaft I81 shown in Fig. 14,

which is provided at its inner end with a cam element 38 that cooperateswith one end of a sliding plunger I89, the cam acting mechanically tomove the plunger to the right, asshown in Fig. 17, in such manner thatits other end engages the valve plunger I85 and forces it positively tothe right against the action biasing of a spring I99 which normallyurges the plunger 1 85 toward its left position. With the valve plungerI85 in the right position as shown, a cannelure I9I in the valve plunger85 establishes communication from the pressure port I83 to a port I 92which leads to the right end of a clutch actuating cylinder I93.Pressure in the right end of the clutch actuating cylinder I93 forces aclutch actuating piston I94 to the left end of the cylinder, therebyuncovering a port 895 at the middle of the cylinder through which thepressure fluid escapes to the lubricating system of the machine. Fluidin the left end of the cylinder I93 is meanwhile exhausted through aport I96 which is then in communication through another cannelure I 91of the valve plunger I85, When the clutch actuating piston I94 moves tothe left, a piston rod I99 projecting from it moves a shifting fork to!to the left likewise. The fork 201 engages a shifting collar 292 whichis connected to actuate the clutch I9, the arrangement being such thatwhen the collar is moved to the left the clutch is moved to disengagedposition.

Upon moving the clutch controlling lever II"I to the right to its otherposition, the cam I88 is turned to a position, shown in Fig. 14, inwhich it releases the mechanical linkage plunger I89 and permits thepilot valve plunger I85 to move to the left under th influence of itsbiasing spring I90. With the plunger I85 in the left position, thepressure port I83 is placed in communication through the cannelure I9Iwith the port I96 leading to th left end of the clutch cylinder I93.Pressure admitted to the left end of the cylinder forces the piston I94to the right whichin turn moves the shifting collar 202 to the right toengage the clutch l9. Fluid in the right end of the cylinder I 93escapes through the port I92 and past the right end of the plunger I 85into With the actuating piston I915 at the right end of the cylinderI93, the lubrication port 195 is again uncovered to permit the flow ofthe pressure fluid into the lubricating system.

As appears in Fig. '7, the lubricating fluid from the port I is forcedupward into the spindle head 2'? through suitable connecting conduits203 one of which discharges above an anti-friction hearing 2% mounted inthe rear wall of the head and serving to support the rearward portion ofth spindle 2h- The spindle is arranged to slide within the inner race ofthe hearing 204 when the quill is is. moved longitudinally, the bearingrace being slidably keyed to the spindle to prevent rel- 11 ativerotation therebetween. 'From the bearing 204 the lubricant drainsthrough a passageway 265 on to a lip 266 from which it flows on to thepick-off gears 86 and 19 to lubricate them. Lubricant draining from thepick-off gears flows through a screened opening 231 into the lower partof the head 21 wher it mingles with other excess lubricant draining fromwithin the head. The lubricant collecting in the bottom of the headreturns to the sump at the bottom of the machine bed through atelescoping tube 268 that constitutes a guard for the verticallydisposed spindle driving shaft 14.

As previously explained, the automatic control system for regulating therate and direction of movement of the table 2| is mounted on the tablefeed'bracket |23 in manner to be removable from the machine with thefeed and rapid traverse driving mechanism as a unit. Hydraulic pressurefor actuating the table control system is derived from an independentpump 2H] that is mounted in'the bracket I23 and arranged to be drivencontinuously by the rapid traverse shaft I31, as shown in Fig. 13. Thepump 2H1 withdraws fluid from the sump through a conduit 2| and forcesit under pressure through a conduit 2|2 to a valve block 243 of thecontrol system that is carried by the bracket I23.

In order that the table 2| may be operated automatically in accordancewith various cycles, means are provided in the control system foreffecting automatic reversal of table movement to movement in theopposite direction either at feed rate or at rapid traverse rate. Forthis purpose, automatic reversing plungers 2 and 2 l 6 are provided atthe respective sides of the rapid traverse trip post 64 in position tobe engaged by reversing trip dogs on the table. For example, if thetable is moving from left to right and a reversing trip dog engages thereversing plunger 2|5, it is moved downward into engagement with apoppet valve plunger 2|1 thereby opening a reverse poppet valve H6 andadmitting pressure fluid from a pressure conduit 2I9 in the valve block2|3, which is connected to the conduit 2|2 delivering pressure from thepump 2 Ill. The pressure fluid flowing through the open poppet valve 2|8follows a conduit 22| into an actuating cylinder formed in the lower endof a reversing valve 222 and there exerts pressure upon a valve plunger223 forcing it upward. When the plunger 223 moves upward, a narrowgroove 224 therein moves into register with a pressure port 225, whichis connected by a conduit 226 with the pressure conduit 2 I9, therebyadmitting pressure fluid through the groove 224 into a longitudinalpasageway 221 in the valve plunger 223 that extends to the lower end ofthe valve 222. Pressure fluid admitted through the passageway 221 exertsadditional pressure on the lower end of the valve plunger 223 tending tomove it upward. This pressure is continued upon the plunger 223 eventhough the reversing poppet valve 2|3 may close because of withdrawal ofthe reversing trip dog from the plunger 2|5, the port 225 being wideenough to maintain the connection with the passageway 221 until thevalve plunger 223 reaches its upper extreme position.

Whenthe reversing valve plunger 223 is in the neutral positionshown inFig. 1'7, pressure fluid from the conduit 226 flows through a rport 228which is then in communication, through a groove 229 in the plunger 223,with a port 230 from which a conduit 23! leads to a low pressure reliefvalve 232 that permits the escape of excessive pressure fluid. As theplunger 223 moves upward in response to a reversing action, the groove229 moves out of register with the port 239 thus interruptingcommunication with the low pressure relief valve 232. This causes thepressure in the system to increase to a predetermined high pressuresuitable for actuating the reversing mechanism, the pressure then beinglimited by a high :pressure relief valve 233 connected directly to thepressure conduit 2|9.

When the reversing valve plunger 223 arrives at its upper position, thepressure port 225 is placed in communication, through a groove 235 onthe valve plunger, with a port 236 from which the pressure fluid flowsthrough a conduit 231 to the right end of a reversing motor cylinder238. Pressure in the right end of the cylinder 238 forces a cooperatingreversing piston 239 to the left, the piston in turn exerting force uponan arm 22! which engages a slot 242 in the piston 239, as shown in Fig.15. The arm 2M is fixed on the tripping sleeve I54 and the arrangementis such that when the piston .239 is moved to either extrem position,the tripping sleeve is turned to a position in which the shifting clutchcollar H4 is engaged with one or the other of the reversing clutch gearsH5 or H6 as previously explained, thereby providing for movement of thetable 2| in' the reverse direction. As the piston 239 moves to the left,fluid in the left end of the cylinder 238, is forced out through aconduit 244 leading to a port 245 that is then in communication througha groove 246 in the valve 223 with an exhaust port 241.

When the piston 239 arrives at its extreme left position, it uncovers aport 25! through which pressure fluid flows into a conduit 25| leadingto a cylinder formed in the lower end of the rate selector I61 Thepressure in the lower end of the selector I61 is exerted upon a piston252 formed on the lower end of the valve plunger I66, forcing theplunger and the rapid traverse tripping post it upward to the rapidtraverse position.

As appears in Figs. 15, 16 and 1'1, the tripping post |64 is providedwith a groove 253 at its lower end that engages one end of a rocker arm254 which is pivotally mounted on a pin 255. The rocker arm 254 isprovided with a cam element which bears upon the stem of a rapidtraverse poppet valve 256 shown at the left in the schematic diagram,Fig. 1'1, the arrangement being such that when the trip post I64 movesupward to rapid traverse position, the poppet valve 256 is depressed andopened. This results in admitting pressure fluid from the pressureconduit 2| 9 through the poppet valve 256 into a conduit 251 that leadsto a port 258 in the reversing cylinder 238.

With the reversing piston 239 in the left position, the port 258 isplaced in communication through a groove 259 in the piston 236, with arapid traverse port 266. From the port 260, a conduit 26| leads to thelower end of the verticall'y'arranged table driving shaft i2!) whichcarries the hydraulically actuated rapid traverse clutch I42. As appearsin Fig. 15, pressure fluid from the conduit 2H flows through a passage-Way/262 formed longitudinally of the shaft l2!) and thence into acylinder 263 where it exerts pressure upon a piston 264 that operates toexert force upon and engage the rapid traverse friction clutch H52.

When the rate selector plunger I66 moves upward under the influence ofpressure exerted through the reversing valve and the reversing cylinder,its lower end uncovers a port 213 which 13' establishes communication.from the conduit 2.2| leading to the lower end. of the reversing valve222 and a conduit 271 leading. to the upper end of the reversing valve.This results in equalizing the pressures on the ends of the reversingvalve plunger 22?; and permits it to return to its central neutralposition under the influence of centralizing springs 2'52 at its ends.As soon as the reversing valve plunger 22% returns to neutral position,communication is Ire-established between the pressure port 228 and theport 23%], thereby permitting the pressure fluid to escape through thelow pressure relief valve 232, the pressure in the system thereuponreturning to the normal low pressure, following the reversing operation.

In the event that it is desired to effect movement in the reversedirection at feed rate instead of simultaneously changing to rapidtraverse rate, a rate controlling valve 215 may be turned, by means of acontrol lever 2W5 mounted on the front of the machine as shown in Fig.1, to close the conduit leading from the reversing cylinder 238 to thelower end of the rate selector l'i'i. With the valve 215 turned to feedposition, communication is established from the conduit 251 through aport 2?? which admits pressure fluid into the selector it? above thepiston 252 and below a sliding neutralizing sleeve 21%. The pressurefluid acting on the sleeve 218 moves it upward in opposition to a spring278 and in so doin uncovers a port ass which establishes an alternativeneutralizing connection between the lower conduit 22E and the upperconduit 21! leading to the respective ends of the reversing valve 222,thereby permitting the valve to return to neutral position.

Reversal in the direction of table movement is accomplished in similarmanner when a reversing trip dog on the table, in moving from right toleft, engages and depresses the other reversing plunger 2%. This resultsin opening a reversing poppet valve 283 that admits pressure from thepressure conduit Zlt into a conduit 284 leading to the conduit 2' whichconnects with an. actuating cylinder at the upper end of the reversingvalve 222. This causes the valve plunger 223 to move downward, againcutting off communication with the low pressure relief valve 232 andestablishing communication from the pressure port 225 through the groove24$, the port 245 and the conduit 24 with the left end of the reversingcylinder 233. This moves the reversing piston 239 to the right, therebyshifting the reversing clutch collar lid to its opposite position andsimultaneously uncovering a port 285 communicating with the rapidtraverse valve actuating conduit 25!. When the pressure in the conduit25!, acting upon the lower end of the rate selector plunger I65, movesthe rapid traverse post it upward and causes the rapid traverse poppetvalve 256 to be opened. as previously explained, the pressure. fluidflowing through the conduit 25? and the port 258, enters a groove 28% inthe reverse piston 233 which is connected by a longitudinal passageway23'! with the groove 259 that communicates with the port 259 and theconduit 26l leading to the rapid traverse clutch.

If it is desired to cause the spindle 2a to stop rotating when the table2i is moving at rapid traverse rate, in order to avoid marring the work,a spindle stop lever 29% on the front of the machine (Fig. 1) is turnedto move a spindle stop valve 2a: to the position shown in Fig. 17. Withthe valve in this position, pressure fluid admitted through the rapidtraverse; poppet valve 256. flows through the valve 291.! into a conduit292 in the valve block 213. which connects with a single lead or pipe293 extending to the main clutch con trolling mechanism at. the rear ofthe machine. As shown, the pipe 28:3 connects with a conduit 294 leadingto: the left end of the pilot valve I thereby exerting. pressure upon.piston 295 formed on the valve plunger and forcing the plunger to theright, against the force of the spring i iti, to the position shown. Aspreviously explained, with. the valve. plunger i525 in. this position,pressure fluid is admitted from the pump 519 to the clutch actuatingcylinder 93 in manner to move the main clutch iii: to disengagedposition, thereby stopping the spindle 26, the table 25 continuing tomove at rapid traverse rate meanwl'iile by reason of the. direct drivinconnection from: the pulley $3. to the rapid traverse shaft Thearrangement for controlling the main clutch by fluid. pressure admittedthrough a single hydraulic lead to a pilot valve is broadly claimed in.the previously mentioned United States Patent No. 2,215.,fi8d. However,in this instance the clutch is caused to be disengaged upon the exertionof pressure through the single control conduit, whereas in the patent,the control pressure is applied to eifect engagement of the clutch. Theadvantage of the present arrangement lies in the factthat the clutchremains engaged regardless of momentary reduction in pressure in thehydraulic system, such as may result from utilizing the pressure fluidfor other shifting operations. Positive operation of the pilot valve todisengage the clutch is assured by the direct mechanical connection.from the clutch controlling lever i i? to the pilot valve plunger.

Vifhenever movement of the table 2! is stopped by disengaging thereversing clutch collar H4 from the reversing clutch gears, eitherthrough the: operation of the automatic stop dogs upon the trippingsleeve ltd or through manual mov ment of the control: lever: we toneutral position, the reversing piston 2:39 is: likewise moved tocentral neutral position. As shown in Fig. 17, when the piston 2'39 isin central position, both the groove 259' and the groove 28% are movedout of communication with the rapid traverse pressure port 255. At the.same time a third groove 29?, which communicates with the longitudinalpassageway Ziil'i, is moved into register with an exhaust port 2%:through which pressure fluid may escape from the rapid traverse clutchactuating cylinder by way of the conduit 26i and the port 266. Thispermits the spring led of the rapid traverse clutch mechanism todisengage the rapid traverse clutch M2 and to engage the synchronizingclutch i 33 for quickly reducing the speed of the table drivingmechanism to the predetermined feed rate, as set forth and claimed inthe previously mentioned United States Patent No. 2,215,684.

With the reversing piston 239 in either the forward or the reverseposition, the rapid traverse drive may be engaged independently of theautomatic reversing control by opening the rapid traverse poppet valve25%, either through movement of the rapid traverse trip post 515d byengagement with a rapid traverse trip dog to move upwardly, or by movingthe manually actuated control lever the outwardly from the machine, aspreviously explained. Furthermore, when the rapid traverse drive isdisengaged by movement of the trip post I64 downward to feed position,

the pressure is simultaneously relieved from the clutch controllingconduit 293 to permit the main clutch to re-engage, unless the pilotvalve is restrained. from movement to clutch engaging position by reasonof the clutch lever actuated cam I88 being in clutch disengagingposition. When the rapid traverse trip post I64 is moved down to feedposition, the rapid traverse poppet valve 256 is permitted to move toclosed position under the influence of a spring 299. By reason of adifferential area on the actuating rod of the poppet valve, the rod iscaused to move upward away from the valve ball thereby exposing thelower end of a longitudinal opening 301 through the rod, through whichthe pressure fluid may escape by way of a bleeder port 382. 7

At the conclusion of a hydraulic rate or direction changing operation,the excess pressure fluid escaping through the low pressure relief valve232 flows into a lubricating system for the mechanism carried by thetable driving bracket I23.

When it is desired to test the hydraulic control system, the tabledriving bracket I23 together with the entire control valve mechanism maybe removed from the machine as previously described. A temporary powerdriving connection may then be applied to the pump 2 In in manner todrive it for supplying hydraulic pressure to the control system duringtesting and experimental operation thereof. After'the control system hasbeen adjusted and tested apart from the machine the entire unit may bereplaced in the machine bed with assurance that it will functioncorrectly when the machine is put in operation. I

From the foregoing detailed explanation of the operation of theexemplifying milling machine herein set forth as a practical embodimentof the present invention, it will appear that there has been provided animproved machine tool structure and actuating transmission and controlmechanism that is especially adapted for convenient operation and thatmay be adjusted and maintained with facility.

Although the illustrative embodiment of the invention has been describedin considerable detail for the purpose of fully disclosing a practicaloperative structure by means of which the invention may be practiced,'itis to be understood that the particular apparatus and control systemherein described are intended to be illustrative only and that thevarious novel characteristics of the invention may be incorporated inother structural forms without departing from the spirit and scope ofthe invention as defined in the subjoined claims.

The principles of the invention having now been fully explained in theforegoing written description of an illustrative embodyingmachine,

we hereby claim as our invention:

1. In a machine tool, a driving mechanism including a disconnectingclutch, a fluid pressure system arranged to move said clutchalternatively to connecting position or to disconnecting position, avalve operatively connected to control said fluid pressure system, meansbiasing said control valve to a position effecting movement of saidclutch to connecting position, fluid pressure means selectively operableto force said valve to a position effecting disconnecting movement ofsaid clutch, control means acting upon said fluid pressure means forcontrolling said valve to thereby effect control of said disconnectingclutch, and other control means acting mechanically upon said valve tomove it to a position effecting disconnecting movement of said clutch.

2. In a machine tool, a driving mechanism including a disconnectingclutch, a fluid pressure system arranged to move said clutchalternatively to connecting position or to disconnecting position, avalve operatively connected to control said fluid pressure system, meansbiasing said control valve to a position effecting movement of saidclutch to connecting position, fluid pressure means selectively operableto force said valve to a position effecting disconnecting movement ofsaid clutch, and manually operable control means selectively actuatableto move said valve mechanically to a position effecting disconnectingmovement of said clutch.

3. In a milling machine having a driven member, means to drive saidmember including a hydraulically actuated disconnecting clutch, a

. source of pressure fluid for actuating said clutch,

a pilot, valve connected to control the flow of fluid from said sourceto said clutch to actuate it, means to urge said pilot valve to theposition in which it eifects engagement of said clutch, pressure fluidactuated means operative to move said pilot valve to the position inwhich it efiects disengagement of said clutch, mean to control the flowof actuating pressure fluid to said pilot valve, and a single fluidconduit operatively connecting said flow control means to said pilotvalve, whereby said pilot valve may be moved from clutch engagingposition to clutch disengaging position by impressing pressure upon itthrough said single fluid conduit. 7

4. In a machine tool, a frame, a working member movable in oppositedirections selectively relative to said frame, power transmissionmechanism including reversing means operative to effect movement of saidmember in said opposite directions selectively, a hydraulic motoroperatively connected to adjust said reversing means, a reversing valveconnected to admit pressure fluid to said motor, hydraulic pressuremeans operatively connected to shift said reversing valve, and tripmechanism operative in response to movement of said working member andfunctioning to control said reversing valve shifting hydraulic means,whereby automatic reversal in the direction of movement of said workingmember may be effected.

5. In a machine tool, a base, a movable machine element slidably mountedon said base,

power actuated means operatively connected to reciprocate said machineelement, trip mechanism mounted in said base in position to be actuatedby said movable element in the course of its reciprocation to controlits actuation, and a control unit removably mounted in said base inposition to be actuated by said trip mechanism, said control unitcomprising a hydraulically operated rate and direction changingmechanism and a pressure pump, said pump being releasably connected tosaid power actuated means, whereby said control unit may be removed inits entirety from said machine for testing under pressure developed bydriving its pump independently of said machine.

6. In a milling machine, a base, table receiving ways formed on thesurface of said base, a

plate removably secured to said base between connecting mechanismrotatably mounted in said said screw and its associated nut and drivingplate concentric with and operatively connected to said screw, thearrangement being such that mechanism. on. said plate may be removedfrom or applied to said bed as a unit, a work table slidably mounted onsaid table ways for longitudinal feeding movement, and. bearing meansattached to the ends. of said table and rotatably 5 receiving the ends.of said screw in manner to transmit feeding movement of said screw tosaid table.

7. In a milling machine, asupporting structure, a movable workingelement. carried by said supporting structure, a power transmissionmechanism connected to drive said movable working element and. includinga. hydraulically actuated disconnecting clutch, a. source of hydraulicpressure for actuating said clutch, a control valve connected to.control. the flow of pressure liquid for engaging or disengaging, saidclutch selectively, means to bias said valve toward the positionresulting in engagementof said clutch, and mechanical control linkageoperatively arranged to force said valve positively to clutchdisengaging position. in opposition tosaid biasing force.

8. In a milling machine. asupporting structure, a movable workingelement. carried by said supporting structure, a power transmissionmechanism connected to drive said movable working element and includinga hydraulically actuated disconnecting clutch, a source of hydraulicpressure for actuating said clutch, a control valve connected tocontrol. the, flow of pressure liquid for engaging or disengaging aidclutch selectively, means to biassaid valve toward the positionresulting in engagement of. said clutch, control means arranged to.apply hydraulic pressure to said valve in opposition to said biasingforce for moving said valve to clutch disengaging position, andmechanical control linkage arranged to apply force to said. valve inopposition to said biasing force for moving said valve positively to.clutch disengaging position. V p 40 9. In a machine. tool. a movableworking element. means for transmitting powertosaidiworking elementincluding a disconnecting: clutch, hydraulic actuating mechanismarranged to engage or disengage said clutch. selectively, a pilot valve.operatively connected to. control said clutch. actuatins mechanism andhaving. operating positions functioning to effect. engagement. anddisengagement of said clutch respectively. resilient means arranged tobias said valve to one of said, positions, and mechanical control lnkage opera tiveselectively to forcesaidvalve to its other position inopposition to. said resilient biasing means.

10. In a machine. tool, a: frame, aworking member movably mounted onsaid frame, a source of, 55 power for operating. said member,transmission" mechanism including a hydraulically actuated disconnectingclutch operatively connected to transmit power from said source to saidmovable fluid pressure for '60 member selectively, a sourceof Iactuating said clutch. a pilot valve. connected to control the flow ofpressure fluid to said clutch and movable to two" operating positionscorresponding to the engaged and disengaged positions of said clutchrespectively, means resiliently urging said pilot valve to clutchengaging position, a manually actuatable clutch controlling lever,mechanical linkage operatively connecting said lever to said pilot valvein manner to provide for positively moving said valve to clutchdisengaging position in opposition to said resilient means, a hydrauliccontrol system for said machine tool, and a single hydraulic conduitleading from said control system to said pilot valve and operative toexert pressure upon said valve to move it to 75 supporting tableslidably mounted on said waysfor longitudinal movement. therea-long, a.table driving nut fixed. in said bed, a table. driving screw threaded insaid nut, means in said bed operatively connected to turn said screw in.said nut, and a bearing disposed to rotatably support each cndof saidscrew, said bearings being. disposed beneath. and attached to therespective ends. of said table and adapted to. pass between said ways onsaid bed, whereby the wayson' said table may be fitted to match the wayson said bed in manner that at each end of the path of travel of saidtable said ways will coincide without either projecting beyond the.other at the trailing end of the table.

12. In a milling machine, a frame, a work supporting table slidablymounted on said frame, means to drive said table including a. feed screwoperatively connected to said table, a driving bracket associated withsaid feed screw and removably mounted. on said. frame; a feed nutmounted in said bracket and cooperatively threaded uponsaid feed screw,a reversing mechanism mounted in said bracket and. operativeiyconnectedto effect relative rotation between said screw and said nut,andpowerdrivenmeans in said. frame having a detachable connection withsaid reversing mechanism, whereby after removing said table from saidframe said driving bracket with said reversing mechanism said nut andsaid screw may be removed as a unitLfrom said frame.

, 13. In aimilling machine, a. frame, a,working element slidably mountedon said. frame. a. driving screw operatively connected to actuate. saidworking, element, a driving bracket attached to said frame, a. nutcarried by said driving bracket in cooperating threaded relationshipwith said driv ing screw, and a power drivenreversing .45.

mechanism carried by said bracket and operatively connected to efiectrelative. rotation between. said. screw and; said nut, the arrangementbeing such that .said screw, said. nut and said reversing mechanism. maybe removed" from said. machine as :a unit. with said. driving bracket.

1 of power mounted in said frame for driving said table, a table drivingand controlling unit detachably mounted in said. frame and arranged totransmit powerfrom said power source to. said table actuating mechanism,a power shaft having splined connection with said driving unit andoperativeiy arranged to transmit power from said power source to saidunit at rapid traverse rate, another power shaftlikewise having splinedconnection with said driving unit and operatively arranged to transmitpower from said source to said unit at feed rate, a table driving shafthaving splined connection with said table actuating mechanism andconnected to transmit power from said driving unit to said tableactuating mechanism at either rapid traverse or feed rate as determinedby the adjustment of said driving frame, table actuating mechanismmounted in said frame and operative to effect sliding movement of saidtable, trip mechanism mounted in said frame in association with saidtable for operation in response to movement thereof, a source of powermounted in said frame for driving said table, a driving and controllingunit including a pressure pump and hydraulic control mechanismdetachably mounted in said frame and interposed between said powersource and said table actuating mechanism, a power shaft having splinedconnection with said driving unit V and operatively arranged to transmitpower from said power source to said unit at rapid traverse rate,another power shaft likewise having splined connection with said drivingunit and operatively arranged to transmit power from said source to saidunit at feed rate, a table driving shaft having splined connection withsaid table actuating mechanism and connected to transmit power from saiddriving unit to said table actuating mechanism at either rapid traverseor, feed rate I as determined by the adjustment of said driving andcontrolling unit, means [in said unit ar-.

ranged to be engaged and actuated by said trip mechanism and operativeupon said hydraulic control mechanism to control the operation ofsaidtable, and means releasably retaining said driving and controllingunit in said frame. the arrangement being such that said unit may bewithdrawn from said frame upon releasing said retaining means anddisengaging said splined shafts whereupon said unit and its hydrauliccontrol mechanism may be tested apart from the machine under powersupplied through a temporary" connection.

16.,In a milling machine comprising a frame, a working element slidablymounted on said frame.

, drive mechanism arranged to effect movement of said element, tripmechanism disposed on said" frame in position to be actuated by saidelement in the course of its movement, a driving and controlling bracketdetachably supported in said frame beneath said element, a verticallydisposed shaft carried by said bracket and detachably eon-'3 nected withsaid element driving mechanism, feed and rapid traverse clutch means onsaid vertical shaft arranged to drive it selectively at feed rate or atrapid traverse rate,'-and a hydraulic control unit mounted in saidbracket in position to be" operated by said trip mechanism on said frameand connected to control said feed and rapid traverse clutch means, thearrangement being such that said bracket together-with said control 20unit and said table driving unit may be removed from said frame as aunitary structure for tes ing and servicing. I

17. In a milling machine, a frame; a work supporting table slidablymounted on said frame,

.a table driving screw, bearings on the ends of said 'bearings may beremoved from said frame as a unit after said table has been removed.

18. In a milling machina'a frame, a pair of ways disposed horizontallyin spaced relationship on said frame, a work supporting table having Iispaced ways corresponding to and cooperating with saidways on saidframe and provided at its ends with sockets between said ways, arotatable table driving screw disposed beneath said table between itsways, bearings on the ends of said screw to support it for rotation, andmeans securing, said bearin s in said sockets at the ends of said table,the arrangement being such that thetable ways'extend the entire lengthof the table in such manner as to overlie and protect all parts of saidways on said frame.

19. In a machine tool having a driven member, a source of power fordriving said member, a

clutch engaging position, hydraulic pressure means operative selectivelyto exert force upon said pilotvalve to move it to clutch disengagingposition in opposition to said biasing means, and a manually operatedmechanical linkage operative selectively to force said pilot valvepositively to clutch disengaging position.

20. In a machine tool, a frame, a working element movably mounted onsaid frame, transmis- 1 sion mechanism arranged toefiect movement ofsaid working element in either direction selectively, hydraulicactuating mechanism operatively connected to adjust said transmissionmechanism, a reversing valve connected to control said hydraulicactuating mechanism, an actuating cylinder formed at each end of saidreversing valve, a reversing plunger valve connected to each of saidactuating cylinders, and trip mechanism arranged to be actuated by saidworking element in the course of its movement and operative upon one orthe other of said reversing plunger valves alternatively to eifectpressure operationof said reversing valve in manner to cause reversingactuation of said transmission mechanism.

' JOSEPH B. ARMITAGE.

ORRIN W. BARKER.

